An AT45DB041B 4Mbit DataFlash is included on the STK600 for non-volatile data storage. This is a high-density flash memory chip with SPI serial interface. Detailed datasheet of the DataFlash can be obtained from the Atmel CD-ROM or from the Atmel web site.
The dataflash can be connected to the I/O pins of the microcontroller sockets. The 4-pin header marked "DATAFLASH" can be used for connecting the SPI interface of the dataflash to the I/O pins on the target AVR microcontroller in the socket. 2-wire cables are included with STK600 for connecting the dataflash to the I/O pins. The connection of the I/O pins is shown on the picture below.
The block schematic of the dataflash connection is shown below, for connection of the dataflash to the AVR hardware SPI interface.
More information about how to use the DataFlash can be found on www.atmel.com.